1346 
MESSRS. J. B. LAWES, J. H. GILBERT, AND M. T. MASTERS, 
total herbage, there was much less growing on this plot of great luxuriance of grasses 
than without manure. Compared with the yield of the three prominent species by 
ammonia-salts alone, the mixture gave considerably more, especially of Conopodium 
denudatum; and compared with the produce from the mineral manure alone, the 
mixture gave an excess of Pumex Acetosa , a less excess of Conopodium denudatum , an 
actual deficiency of Achillea Millefolium , and also a considerable deficiency of those 
species taken collectively, each of which only occurred in fractional quantity. 
Upon the whole, then, the mixture of nitrogenous and mineral manure has given a 
produce characterised by great luxuriance of gramineous species, by an almost total 
exclusion of Leguminosse, and by the considerable prevalence of only very few mis¬ 
cellaneous species, representing three very distinct natural orders : the Polygonacece , 
the Umbelliferce , and the Composites, the species themselves being of very marked, as 
well as of very different, characters of growth. 
The general aspect of the plot was also very distinct from that of either of the plots 
with which it is compared. Not only was the herbage almost exclusively gramineous, 
but the grasses were very luxuriant, generally developing broad leaves and strong 
stems, with considerable tendency to consolidation of tissue and to flowering, seeding, 
and maturation. The total absence of Leguminosse, and of most of the usually 
prevalent Miscellanea^, only two or three of which show any degree of prominence, also 
give to the appearance of the plot a marked character. Indeed, the herbage is too 
exclusively gramineous, and too coarse, to constitute even moderately good hay. 
8. Ammonia-salts (400 lbs. per acre), with mixed mineral manure including 
potass, and 2000 lbs. cut wheat straw; Plot 13. 
The mixture annually supplied to this plot contained precisely the same descrip¬ 
tion and amount of ammonia-salts, and precisely the same complex mineral manure, 
including potass, as that applied to plot 9, but with 2000 lbs. of cut wheat straw in 
addition. The object was to try the effect of silica, and of carbonaceous organic matter, 
supplied somewhat in the same condition as in dung. The straw would, of course, 
contain a certain amount of other mineral constituents besides silica, and the amount 
annually supplied contained also about 9 lbs. of nitrogen. Undoubtedly, however, the 
manurial constituents of the straw would be for the most part very slowly available. 
Compared with plot 9 without the straw, plot 13 with it gave an average of several 
hundred pounds more produce per acre annually ; and, like plot 9, it has yielded rather 
more during the last five years than during the first 20. Over the 20 years, and 
probably since, plot 13 has yielded more mineral matter, and more nitrogen, per acre per 
annum; in fact, more of each individual mineral constituent than plot 9, especially of 
potass and phosphoric acid. Of silica, plot 13 furnished rather less in the later than 
in the earlier years; but whilst in the earlier years the two plots yielded practically 
the same amount, the amount annually taken up fell off in the later years very con¬ 
siderably on plot 9, but much less on plot 13 ; so that the increased yield of silica 
